SDBox Mini for Amiga

SDBox in a standard DB25 plastic shell

Rev. 2B

Video:
https://drive.google.com/file/d/1fLwmIyUeHZX4sln5bpJfz5QkDGD-QTOf/view?usp=sharing

+5V taken from floppy port with this USB-C dongle
https://github.com/jbilander/Amiga_DB23_to_USB_C_power_only_adapter

Rev. 2A

This hardware uses the firmware written by Niklas Ekström, available here...
https://github.com/niklasekstrom/amiga-par-to-spi-adapter

...or use my fork if you also want the Activity LED to blink (it also includes a batch-script flashSDBoxMini.bat for flashing the Mini)
https://github.com/jbilander/amiga-par-to-spi-adapter

Connecting the Arduino to program the SDBox Mini

(Programmer)
Arduino as ISP - SDBox Mini 
------------------------------------
D13 (SPI) SCK  - Pin 3 (ICSP) SCK
D12 (SPI) MISO - Pin 1 (ICSP) MISO
D11 (SPI) MOSI - Pin 4 (ICSP) MOSI
D10 (SPI) SS   - Pin 5 (ICSP) /RESET
          5V   - Pin 2 VCC
          GND  - Pin 6 GND

On the Nano V3 the pins on the ICSP-header can be utilized connected like below. There is no need to solder an ICSP-header on the mini, you can just hold the connector against the footprint while programming.

To use the Arduino Nano as ISP it first has to be flashed with the ArduinoISP-sketch which is available under File->Examples in the Arduino IDE, or you can use the attached batch-script flash_Arduino_as_ISP.bat and binary hex ArduinoISP.ino.arduino_standard.hex I have put them in a zip-file under Releases ArduinoISP.zip. Alter the com port in the script file to suit your machine and execute it from a command-prompt. Now you are ready to flash the SDBox-Mini via the Arduino.

Flash the SDBox Mini using the Arduino as ISP

This requires that you already have built the main.hex file in the avr-folder, then execute flashSDBoxMini.bat from a command prompt:

Connecting a RPi4 to program the SDBox Mini

Warning!
Connection of a GPIO to a voltage higher than 3.3V will likely destroy the GPIO block within the SoC.

I used my Logic level converter board in between the devices and powered from the RPi's +5V

First install avrdude:

sudo apt install avrdude

Now copy the default config file to a new file under /home/pi

cp /etc/avrdude.conf ~/avrdude_gpio.conf

Add this entry last in the file using your editor (vim or nano) and save the file:

#------------------------------------------------------------
# Linux GPIO configuration for avrdude
# Change the lines below to the GPIO pins connected to the AVR
#------------------------------------------------------------
programmer
    id        = "pi_1";
    desc      = "Use the Linux sysfs interface to bitbang GPIO lines";
    type      = "linuxgpio";
    reset     = 12;
    sck       = 24;
    mosi      = 23;
    miso      = 18;
;

Now cd into /home/pi and make the script-file executable:

chmod 755 ./flashSDBoxMini.sh

With all jumper-wires connected and main.hex built, run the script flashSDBoxMini.sh (OR type the line below and hit enter)

sudo avrdude -C ~/avrdude_gpio.conf -c pi_1 -v -p m328p -Uflash:w:main.hex:i -Ulfuse:w:0xe6:m -Uhfuse:w:0xdf:m -Uefuse:w:0xfc:m

Caveats

One caveat to keep in mind when building and programming Rev.2A (the first revision of the Mini) is the flashing of the fw can't be done with U4 chip in place as it drives/conflicts with MISO on ICSP (In-Circuit Serial Programming). For Rev. 2B PCB use 74AHCT1G126 instead of 74LVC1G17, same package/footprint. This solves the flashing conflict problem. You put a Jumper-shunt on JP1 (on Rev 2B PCB) while flashing and remove it afterwards.

Building SDBox Mini

Start with the 16 MHz Crystal, C8, C9 and the ATMega328P.

At this point you should be able to flash the Firmware to the ATMega using either an Arduino as ISP or a Raspberry Pi.

Continue with the rest of the components on the front side, and then the back side. I usually pre-tin the C1 pads and use hot air to put the C1-Capacitor in place.

Verify the Micro USB-jack and the voltage levels...

Now it's time to drill the holes for the LEDs, begin with a 1 mm drill and then step up to 2 mm and finally 3 mm. Be very careful when drilling to get a nice clean 3mm hole, it's very easy to slip and the hole gets oval or offset.

Short video showing copying a 8 MB file from the HD to the SD-card on my A1200. +5V to power the SDBox I nicked from the floppy port DB23->microUSB (Howto make such a cable here ).
Video:
https://i.imgur.com/mF9Bp4C.mp4

Amiga installation:

Download Amiga.zip from Releases.

• Put latest fat95 into L: (download from Aminet)
• Put SD0 and SD0.info into Devs: (from Amiga.zip)
• Put spisd.device into Devs: (from Amiga.zip)
• Put Mount_SDCARD and Mount_SDCARD.info anywhere on your HD or floppy disk.
• Put a FAT/FAT32 formatted MicroSD-card in the card reader (Max 4 GB partitioned).
• Double-click the Mount_SDCARD icon.

Disk icon should now appear on the Workbench screen.

Happy Hackin´

BOM Rev. 2B (Same as 2A with the addition)

BOM Rev. 2A